The present invention relates to traffic barriers and more particularly to manually retractable bollards.
Bollards are barriers that are used on urban plazas to prevent pedestrians or vehicles from entering an area. Since having a permanent bollard stationed to prevent access by vehicles to a particular plaza would result in blocking access by emergency vehicles it is very helpful if bollards would be retractable. As a result of the desire to have a bollard that is retractable, prior art bollards tend to be complicated to manufacture and operate and many of them are inoperable by single individuals.
Besides being complicated to manufacture and operate, many prior art retractable bollards require excavation of large areas of pavement. Some prior art retractable bollards cannot be made to too high a height since it would be too heavy.
Many prior art bollards operate based on hydraulic mechanisms or pneumatic springs which are affected by power and mechanical failure. Other prior art bollards require electrical power. Certain prior art bollards are manually operable but suffer from other drawbacks including but not limited to the fact that they are not sturdy and they do not retract fully below grade. U.S. Pat. Nos. 3,660,935, 4,576,508, 4,715,742, 5,481,828, 5,975,792 disclose various kinds of bollards.
The present invention addresses these concerns and provides a bollard that has all of the appropriate and necessary characteristics. It is not necessary to excavate a large square foot area of the pavement in order to install the bollard of the present invention. The bollard of the present invention can be made to fit any suitable size.
In sum, the bollard of the present invention is retractable: and of simple construction and is made of stainless steel to limit site maintenance such as panting, repair of corrosion, etc. The bollard comprises a cylindrical post that is slidably disposed in a sleeve below grade level. In active position, the post can be grasped by a handle and pulled up by human effort to where only a lower portion remains submerged underground. The lower portion of the cylindrical post has spiral threading that mates with spiral grooves at an upper sleeve portion of the sleeve when the post is turned after first raising the post to an appropriate point. A safety lock permits the post to be raised from a stored position to an active position and a double lock that prevents it to from being easily lowered by mischievous individuals from the raised active position to the stored position. These and other important features will be described in further detail below.
The following objects and advantages of the present invention are:
(a) to provide a simple to use, simple to manufacture and versatile stainless steel bollard that can be made to the desired size and height which comprises a post that slides in an out of a sleeve located below grade level,
(b) to provide a bollard that does not require excavation of a large square foot area of pavement to install,
(c) to provide a bollard that is manually operable and retractable so that access can be blocked to a particular area while not denying access to the area by emergency vehicles when appropriate,
(d) to provide a bollard that can be raised and lowered with a handle,
(e) to provide a bollard that has a lock that has to be unlocked before the post can be raised from a stored position to an active position and a double lock that governs whether the post can be lowered from the raised active position to the stored position,
(f) to provide a bollard having a post that has spiral threading and a sleeve that has spiral grooves so that when the bollard that is raised to a point where an upper part of the spiral threading of the post is adjacent to the lower part of the spiral grooves of the sleeve, the post may be turned clockwise to its fully raised position.
(g) to provide a bollard that has a cushion to cushion the impact of lowering the post,
(h) to provide a bollard that has a handle including a smooth outer surface of a top edge that can receive engraved lettering identifying the plaza or street location, and
(i) to provide a bollard that allows a rope to be inserted into it in raised position so that the bollard can be connected to other barriers for cordoning off an area such as to enable queuing of people.